If there was a single target that caused Allied airmen to blanch in the fall of 1943 and the spring of 1944, it was undoubtedly Ploesti. The Romanian oil refining complex had the dubious honor of being the second of the three most heavily defended targets in Europe – the first was Berlin and the second was Weiner-Neustadt in Austria. Ironically, the Allies weren’t aware of the defenses concentrated around the refineries until they found out the hard way on August 1, 1943. Perhaps they should have anticipated that the Germans would mount an aggressive defense of the refinery complex. After all, British Prime Minister Sir Winston Churchill thought the refineries so important that he believed that the destruction of the refineries would deal a “knock-out blow” to the entire German war effort. The Ploesti complex produced 60% of the Axis’ petroleum products in Europe; the remainder was spread over many small complexes in Germany and the occupied countries. Ploesti was identified as one of the most important targets in Europe by the Allies at the beginning of the war – the problem was that it lay out of range of all the British and American bombers except for one airplane, the Consolidated B-24 Liberator, and until the summer of 1943 there weren’t enough of them to make an effective strike. The Soviet air force had bombers that could reach Ploesti and did attack the refineries a few times but did little damage.
The Germans were also well aware of the distance involved and considered the city’s location to be Ploesti’s best defense – until June 1942 when a small force of American Liberators made an ineffective attack on the refineries on the night of June 11. The Liberators were from the Halverson Detachment, a special mission that had been organized early in 1942 for deployment to China to serve as the nucleus of a bomber force for a sustained bombing campaign against the Japanese home islands. But the plan for a strategic bombing campaign was thwarted when Japan responded to the militarily ineffective Doolittle Raid by mounting an offensive in China and capturing the regions where the Allies planned to establish bases – and killed more than a quarter of a million Chinese civilians in the process. No longer with a mission in China, the Halverson B-24s were halted in Africa and sent to the Middle East to make a strike on Ploesti. Instead of becoming the nucleus of a bomber force in China, they became the nucleus for a heavy bomber group in the Middle East.
The British Royal Air Force had been working on a plan to bomb the oil refineries at Ploesti for more than two years and when HALPRO, as the detachment had been designated, arrived in Egypt they gave their plan to the Americans. The RAF plan called for a strike force to depart from Egypt and fly over the Aegean Sea for a rendezvous near the target at daybreak with a return to Egypt over the same route. Halverson decided instead to return to Habbaniyeh, an airfield in Iraq, even though it would mean violating the neutral airspace over Turkey. Late on June 11 thirteen B-24s took off from Fayid, Egypt for the flight over the Mediterranean. Twelve airplanes proceeded to the target individually and arrived over Ploesti at dawn. Some crews bombed through a 10,000-foot overcast while others dropped below the clouds to bomb. The small force wasn’t intercepted, and all twelve crews made it to safety, with four landing at Habbaniyeh as planned, three others landing at other fields in Iraq and two at Aleppo while four were interned in Turkey. Another crash-landed. In spite of the lack of enemy action, the toll on Allied aircraft was heavy since five of the thirteen airplanes were removed from further combat use.